uMake exports images in a transparent PNG file format to make allow for maximum flexibility in working with the image in your favorite image editor.
One side effect of exporting to a transparent PNG is that when viewed on an iOS device like an iPad int he photo gallery, the image shows up with a black background which could make it difficult to see if you have just a line sketch for example.
One work around that we have discovered is the following:
1. Export a still image using the export function found in the top menu.
2. To view the exported image, open up the Photos app and navigate to Camera Roll.
3. Tap on the exported image. This is when you will notice the black background.
4. Tap 'Edit' to edit the image.
5. Tap on the Crop icon. In the upper left corner you will notice a "rotate" button.
6. Rotate the image 4 times (360º)
7. Tap Done.
(Credit to beta tester Aurelien François for discovering and sharing this workaround)
We recently created a video that will help walk you through this process: